THE THREE AMERICANS being laid to rest at Arlington National Cemetery today -- Deputy Assistant Secretary of State Robert C. Frasure, Deputy Assistant Secretary of Defense Joseph Kruzel and Air Force Colonel S. Nelson Drew -- deserve the highest honors this nation can bestow. Armed only with ideas and a fierce determination to make reason and justice prevail against hatred and greed, they fought for their nation's principled cause on the front lines of one of the ugliest wars of their lifetimes. They go to their graves as true heroes of peace.

Certainly the loss of these three brave men represents a grave setback to the cause to which they had devoted their lives: a sustainable peace settlement in Bosnia and the rest of the former Yugoslavia. While they were not policy makers, they were among the small handful of diplomats whose intimate knowledge of the war and connections among the combatants made the hope of a workable policy possible. In the short term, at least, they may well be irreplaceable.

Invoking the myth of Sisyphus, Secretary of State William Perry has vowed to form a new diplomatic team and press on with the administration's peace initiative until "we put that rock on top of the mountain."

A good place to start would be Mount Igman, outside Sarajevo, where Frasure, Kruzel and Drew met their accidental deaths on a hazardous dirt track along which cowardly Serbian gunners have killed dozens of civilians. Since the Serbs forced the closure of the Sarajevo airport in April, the road has become the besieged Bosnian capital's final, tenuous link to the outside world -- a link that the new U.N. rapid reaction force should finally be used to secure.